Immobilized palladium complexes

ABSTRACT

The invention relates to immobilized palladium complexes, to a process for their preparation, to their use as catalysts and to a process for the preparation of arylamines using immobilized palladium complexes.

[0001] The invention relates to immobilized palladium complexes, to aprocess for their preparation, to their use as catalysts and to aprocess for the preparation of arylamines using the immobilizedpalladium complexes.

[0002] Arylamines, especially substituted anilines, are of greatindustrial importance as precursors for dyestuffs, fine chemicals,pharmaceuticals and agrochemicals. Arylamines are generally prepared onthe industrial scale by the nitration of an appropriate aromaticcompound, followed by hydrogenation. As nitrations are carried out underdrastic reaction conditions, a large number of complex substitutedarylamines cannot be prepared satisfactorily in this way, if at all.

[0003] Arylamines can also be prepared by the ammonolysis of phenols andchlorobenzenes (K. Weissermel et al., Industrial Organic Chemistry,1993, 2nd edition, VCH Verlagsgesellschaft, Weinheim, 370-373). Again,because of its drastic reaction conditions, this procedure is unsuitablefor the preparation of substituted arylamines.

[0004] U.S. Pat. No. 5,576,460 describes a process for the preparationof arylamines by reacting metal amides, prepared in situ, with aminesusing palladium complexes carrying phosphine ligands. The disadvantageof this process is that the phosphine ligands required for this purposeare normally expensive, air-sensitive and difficult to handle. Thepalladium complexes produced therefrom in situ are also air-sensitiveand susceptible to degradation reactions.

[0005] Nolan et al., Organic Letters Vol. 1, No. 8, 1999, 1307-1309,describe the preparation of arylamines using palladium catalystscarrying heterocyclic carbenes as ligands. In comparison with phosphineligands, heterocyclic carbenes have a high thermal and chemicalstability. However, one disadvantage of the palladium catalysts used byNolan et al. is that they have to be removed from the reaction mixturewhen the reaction has ended, which is costly. Another disadvantage isthat the catalyst cannot be recycled, i.e. re-used in another reaction.

[0006] Surprisingly, immobilized palladium complexes have now been foundwhich are distinguished by their ease of preparation, their high thermalstability and their insensitivity to oxygen and moisture. The complexesaccording to the invention have a high activity and selectivity and canpreferably be used as catalysts for the preparation of arylamines. Whenthe reaction has ended, the catalysts can easily be separated from thereaction mixture and used in another reaction without loss of activity.

[0007] The complexes according to the invention are supported compoundsof formula (I):

[0008] in which

[0009] X is halogen, trifluoromethanesulphonate, acetylacetonate oracetate,

[0010] L is a radical of the formula P(D)₃, D being alkyl, cycloalkyl,aryl, aralkyl, alkylaryl or heteroaryl, or

[0011]  a radical of the formula N(E)₂, E being alkyl, cycloalkyl, aryl,aralkyl, alkylaryl or heteroaryl, or

[0012]  a radical of formula (II):

[0013] in which

[0014] B¹ and B² are identical or different and are a radical tocomplete a heterocycle, especially

[0015] R¹-R⁴ are identical or different and are a divalent radical fromthe group comprising alkyl, cycloalkyl, aryl, aralkyl and alkylaryl,each of which is optionally substituted by COO—(C₁-C₄-alkyl),O(C₁-C₄-alkyl) or CONH₂, and

[0016] A¹-A⁴ are identical or different and are hydrogen or a chemicalbond from the group comprising —CONH—, —CO—O—OC—, —COO—, —O— and

[0017]  via which the complex is bonded to the support, with the provisothat at least one A is other than hydrogen.

[0018] The terms used above are defined as follows:

[0019] “Halogen” denotes F, Cl, Br or I.

[0020] “Alkyl” denotes linear or branched —C₁-C₁₂-alkyl, for examplemethyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl,neopentyl, hexyl, heptyl, isoheptyl, 2-ethylhexyl or octyl.

[0021] “Cycloalkyl” denotes —C₃-C₈-cycloalkyl, for example cyclopropyl,cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl or cyclooctyl.

[0022] “Aryl” denotes —C₆-C₁₄-aryl, for example phenyl, naphthyl orbiphenyl.

[0023] “Aralkyl” denotes —C₁-C₁₂-alkyl-C₆-C₁₄-aryl, the free valencybeing on the alkyl moiety, for example phenylmethyl, phenylethyl,naphthylmethyl, naphthylethyl, diphenylmethyl or triphenylmethyl.

[0024] “Alkylaryl” denotes —C₆-C₁₄-aryl-C₁-C₁₂-alkyl, the free valencybeing on the aryl moiety, for example tolyl, ethylphenyl, xylyl,methylnaphthyl or ethylnaphthyl.

[0025] “Heteroaryl” denotes unsaturated rings having 5 or 6 atoms andcontaining one or two oxygen atoms and sulphur atoms and/or one to fournitrogen atoms, with the proviso that the total number of heteroatoms isfour or less, for example furan, thiophene, pyridine, pyrrole orimidazole, or bicyclic rings in which the 5- or 6-membered rings definedabove are fused to a benzene or pyridine ring, for example purines,benzopyran or benzimidazole.

[0026] The complexes according to the invention are preferably supportedcompounds of formula (I) in which

[0027] X is halogen,

[0028] L is a radical of the formula P(D)₃, D being a radical from thegroup comprising cyclohexyl, phenyl, naphthyl and tolyl, or a radical offormula (II):

[0029] in which

[0030] B¹ and B² are identical or different and are

[0031] R¹-R⁴ are identical or different and are a divalent radical fromthe group comprising alkyl, cycloalkyl, aryl, aralkyl and alkylaryl,each of which is optionally substituted by COO—(C₁-C₄-alkyl),O(C₁-C₄-alkyl) or CONH₂, and

[0032] A¹-A⁴ are identical or different and are hydrogen or a chemicalbond from the group comprising —CONH—, —CO—O—OC—, —COO—, —O— and

[0033]  via which the complex is bonded to the support, with the provisothat at least one A is other than hydrogen and the support is selectedfrom the group comprising inorganic supports and polymeric supports.

[0034] The complexes according to the invention are particularlypreferably compounds of formula (I) in which

[0035] X is I,

[0036] L is

[0037] B¹ is

[0038] R¹ and R³ are identical and are a divalent radical—(C₁-C₆-alkyl)-, preferably —CH₂—,

[0039] R² and R⁴ are identical and are a divalent radical—(C₁-C₆-alkyl)-, preferably —(CH₂)₃,

[0040] A¹ and A³ are identical and are hydrogen, and

[0041] A² and A⁴ are identical and are a chemical bond from the groupcomprising —CONH—, —CO—O—OC—, —COO—, —O— and

[0042]  and the support is an inorganic support from the groupcomprising silica gel, magnesium oxide and aluminium oxide, or apolymeric support from the group comprising polyester, polyether,polyethylene, polypropylene and polystyrene.

[0043] Very particularly preferred supports are functionalizedpolystyrenes crosslinked with divinylbenzene, such as thoseconventionally used in solid phase peptide chemistry or for solid phasesynthesis.

[0044] The complexes according to the invention can be prepared in situor separately. This can be done by first fixing the ligands to thesupport. The fixed ligands can then be converted in situ or separatelyto the complexes according to the invention.

[0045] Another possibility for separate preparation is first to preparethe free complex from ligands and Pd compound and then to fix it to thesupport in order to prepare the complexes according to the invention.

[0046] The invention further relates to a process for the preparation ofcompounds of formula (I) which is characterized in that compounds offormulae (III) and (IV):

[0047] in which

[0048] B¹ and B² are identical or different and are a radical tocomplete a heterocycle, especially

[0049] R¹-R⁴ are identical or different and are a divalent radical fromthe group comprising alkyl, cycloalkyl, aryl, aralkyl and alkylaryl,each of which is optionally substituted by COO—(C₁-C₄-alkyl),O(C₁-C₄-alkyl) or CONH₂,

[0050] G¹-G⁴ are identical or different and are hydrogen, COOH,CO—O—CO(C₁-C₄-alkyl), COO(C₁-C₄-alkyl), COCl, CO(C₁-C₄-alkyl), COH, NH₂,NH(C₁-C₄-alkyl), OH, Si(O—C₁-C₄-alkyl)₃ or OCN, with the proviso that atleast one G is other than hydrogen, and

[0051] Y is an anion from the group comprising Cl, Br, I,C₁-C₄-alkylsulphonate, C₆-C₁₄-arylsulphonate, hexafluorophosphate andtetrafluoroborate,

[0052] or compounds of formulae (III) and P(D)₃, or compounds offormulae (III) and N(E)₂, are reacted with Pd(II) compounds in thepresence of a base, and the reaction product, a Pd/N-heterocycliccomplex, is immobilized on a support which has groups reactive towardsG, other than hydrogen. The above-described process according to theinvention will be called synthesis variant A hereafter.

[0053] The invention further relates to a process for the preparation ofcompounds of formula (I) which is characterized in that compounds offormula (III) or compounds of formulae (III) and (IV) are immobilized ona support which has groups reactive towards G, other than hydrogen, andwith Pd(II) compounds and—in the case where only compounds of formula(III) are immobilized on a support—with P(D)₃ or N(D)₂ in the presenceof a base. The above-described process according to the invention iscalled synthesis variant B hereafter.

[0054] The compounds of formulae (III) and (IV) are preferablyimidazoles, imidazolines, triazoles or benzimidazoles and particularlypreferably imidazoles.

[0055] The compounds P(D)₃ are preferably those in which D is a radicalfrom the group comprising cyclohexyl, phenyl, naphthyl and tolyl.

[0056] The Pd/N-heterocyclic complex is preferably prepared usingcompounds of formulae (III) and (IV) in which

[0057] R¹-R⁴ are identical or different and are a divalent radical fromthe group comprising —(C₁-C₆-alkyl)—, —(C₆-C₁₄-aryl)— and—(C₁-C₄-alkyl-C₆-aryl)—,

[0058] B¹ and B² are identical or different and are

[0059] G¹ and G³ are hydrogen, and

[0060] G² and G⁴ are identical or different and are COOH,CO—O—CO(C₁-C₄-alkyl), COO(C₁-C₄-alkyl), COCl, CO(C₁-C₄-alkyl), NH₂,NH(C₁-C₄-alkyl), Si(O—C₂-C₄-alkyl)₃, OCN or OH.

[0061] Particularly preferably, the compounds of formulae (III) and (IV)used are those in which

[0062] B¹ and B² are

[0063] R¹ and R³ are identical and are a divalent radical—(C₁-C₆-alkyl)—, preferably —CH₂—,

[0064] R² and R⁴ are identical and are a divalent radical—(C₁-C₆-alkyl)—, preferably —(CH₂)₃—,

[0065] G¹ and G³ are hydrogen, and

[0066] G² and G⁴ are identical and are COOH, CO—O—CO(C₁-C₄-alkyl),COO(C₁-C₄-alkyl), COCl, NH₂, OH, Si(O—C₁-C₄-alkyl)₃ or OCN, preferablyCOO—(C₁-C₄-alkyl).

[0067] The compounds of formulae (III) and (IV) can be prepared e.g.analogously to Herrmann et al., Chem. Eur. J. 2, No. 12, 1996,1627-1636.

[0068] Each of the compounds of formulae (III) and (IV), P(D)₃ and N(D)₂is preferably used in an amount of 0.6 to 4 equivalents, preferably of0.8 to 3 equivalents and particularly preferably of 0.9 to 2equivalents, based on the Pd(II) compounds.

[0069] The Pd(II) compounds used can be palladium acetate, halides,nitrate, carbonate, ketonate or acetylacetonate. It is preferred to usePd(OAc)₂, Pd(acac)₂ or PdCl₂ and particularly preferred to use Pd(OAc)₂.

[0070] The bases used are preferably alkali metal and alkaline earthmetal alcoholates such as lithium tert-butylate, sodium tert-butylate orpotassium tert-butylate, and alkali metal and alkaline earth metalcarbonates such as sodium carbonate or potassium carbonate. It ispreferred to use alkali metal alcoholates or alkali metal carbonates andparticularly preferred to use sodium tert-butylate or potassiumcarbonate. The base is preferably used in an amount of 0.5 to 2equivalents, especially of 1 to 3 equivalents and particularlypreferably of 1.2 to 2 equivalents, based on the Pd(II) compound.

[0071] The supports used are preferably inorganic supports or polymericsupports. Particularly preferably, the support is selected from thegroup comprising silica gel, magnesium oxide, aluminium oxide,polyester, polyether, polyethylene, polypropylene and polystyrene.

[0072] The processes according to the invention are preferably carriedout in the presence of alkali metal iodides such as LiI, Nal, KI or CsI.It is preferred to use NaI or KI and particularly preferred to use Nal.The alkali metal iodides are preferably used in an amount of 2 to 6equivalents, preferably of 3 to 5 equivalents, based on the Pd(II)compounds.

[0073] When the Pd/N-heterocyclic complexes are prepared by synthesisvariant A, the reaction is preferably carried out in an inert solvent,preferably in a polar solvent and particularly preferably intetrahydrofuran or ethanol.

[0074] The reaction takes place for example at temperatures of 0° C. to100° C., preferably of 10° C. to 40° C. and particularly preferably of18° C. to 25° C.

[0075] The reaction conventionally takes place with the exclusion ofwater, preferably under an inert gas such as nitrogen, argon or helium.

[0076] When the Pd/N-heterocyclic complexes are prepared by synthesisvariant A, the abovementioned starting compounds can be placed in onereaction vessel. The solvent can then be added and the reaction mixtureis preferably stirred for a few hours at room temperature. The progressof the reaction can be monitored by thin layer chromatography. When thereaction has ended, the solvent can be stripped off and the residuepurified by column chromatography.

[0077] The Pd/N-heterocyclic complexes prepared by synthesis variant Aare preferably immobilized on a support by reacting the Pd complex withthe support in an amount corresponding to the desired subsequent loadingof the support. If appropriate, the groups G of the Pd/N-heterocycliccomplexes or the reactive groups of the support are activated withsuitable reagents. For example, amino groups can be converted bycompounds like triethylaluminium to more reactive diethylaluminiumamides, or carboxyl groups can be converted to active esters oranhydrides. In the reaction, the functional groups of the carbenecomplex react with the reactive groups of the support to form a chemicalbond. If appropriate, free reactive groups on the support which arestill present after the reaction can be converted with suitable reagentsto unreactive groups.

[0078] To immobilize the Pd/N-heterocyclic complexes on supports, it ispossible to place the complex together with the support, optionally withthe addition of activating reagents or condensing agents, in a solvent.In the case of polymeric supports, it is preferred to use solvents inwhich the polymeric support is in the swollen state. The reactionmixture is preferably mixed thoroughly, this thorough mixing preferablybeing effected by shaking because vigorous stirring can reduce the sizeof the supports. The reaction mixture is heated if appropriate. Theprogress of the reaction can be observed for example by solid phaseFT-IR spectroscopy. When the reaction has ended, the support can befiltered off, washed and dried.

[0079] The immobilization of the Pd/N-heterocyclic complexes oninorganic supports can be carried out analogously to J. Blümel, Inorg.Chem. 33, 1994, 5050-5056.

[0080] The immobilization of the Pd/N-heterocyclic complexes onpolymeric supports can be carried out analogously to F. R. Hartley,Supported Metal Complexes, D. Reidel Publishing Company, Dordrecht,Boston, Lancester, Tokyo 1985, 170-174.

[0081] It is preferred to immobilize the Pd/N-heterocyclic complexes ona polymeric support, preferably on polystyrene crosslinked withdivinylbenzene and particularly preferably on a Merrifield resin, i.e. achloromethylated polystyrene resin crosslinked with divinylbenzene, oron aminomethylated polystyrene crosslinked with divinylbenzene.

[0082] When synthesis variant B is used, the fixing to the support canbe carried out analogously to the above description. The reaction of thesupported compounds (III) and/or (IV) or P(D)₃ or N(E)₂ with Pd(II)compounds can also be carried out analogously to synthesis variant A.

[0083] The preparation of Pd/N-heterocyclic complexes with compounds offormulae (III) and P(D)₃ or N(E)₂ can be carried out analogously toEnders et al., Chem. Ber. 129, 1996, 459-463.

[0084] The compounds of formula (I) are suitable for example ascatalysts for carbonylations, alkylations and hydrogenations and for thepreparation of arylamines.

[0085] The compounds of formula (I) are preferentially suitable ascatalysts for the preparation of arylamines.

[0086] The invention further relates to a process for the preparation ofarylamines of formula (V):

Ar—NR⁵R⁶  (V)

[0087] in which

[0088] Ar is phenyl, naphthyl, pyridyl, pyridazinyl, pyrimidyl,pyrazinyl, pyrryl, thiophenyl, furyl, imidazolyl, oxazolyl, isoxazolyl,thiazolyl or triazolyl, and the abovementioned radicals optionally carryone or more substituents from the group comprising C₁-C₈-alkyl,C₃-C₈-cycloalkyl, C₁-C₈-alkoxy, C₁-C₈-acyloxy, C₆-C₁₄-aryl,C₆-C₁₄-aryloxy, halogen, C(halogen)₃, NO₂, NH₂, NH(C₁-C₈-alkyl),N(C₁-C₈-alkyl)₂, NHCOR, NHCHO, NHCOOH, NHCOOR, OH, CN, COOH, CHO,CO(C₁-C₈-alkyl), CO(C₆-C₁₄-aryl), CO₂(C₆-C₁₄-aryl), CO₂(C₁-C₈-alkyl),CONH₂, SO₃H, SO₂R, SOR, PO(C₆-C₁₄-aryl)2, PO(C₁-C₈-alkyl),Si(C₁-C₈-alkyl)₃ and heteroaryl, R being C₁-C₄-alkyl, and

[0089] R⁵ and R⁶ independently of one another are hydrogen,C₁-C₁₂-alkyl, C₃-C₈-cycloalkyl or C₆-C₁₄-aryl, the abovementionedradicals optionally carrying one or more substituents from the groupcomprising C₁-C₈-alkyl, C₃-C₈-cycloalkyl, C₁-C₈-alkoxy, C₁-C₈-acyloxy,C₆-C₁₄-aryl, C₆-C₁₄-aryloxy, halogen, C(halogen)₃, NO₂, NH₂,NH(C₁-C₈-alkyl), N(C₁-C₈-alkyl)₂, NHCOR, NHCHO, NHCOOH, NHCOOR, OH, CN,COOH, CHO, CO(C₁-C₈-alkyl), CO(C₆-C₁₄-aryl), CO₂(C₆-C₁₄-aryl),CO₂(C₁-C₈-alkyl), CONH₂, SO₃H, SO₂R, SOR, PO(C₆-C₁₄-aryl)₂,PO(C₁-C₈-alkyl), Si(C₁-C₈-alkyl)₃ and heteroaryl, R being C₁-C₄-alkyl,or together are a ring having up to 5 C atoms, it being possible for oneC atom to be replaced by O or N,

[0090] by reacting aryl compounds of formula (VI):

Ar—Q  (VI)

[0091] in which

[0092] Ar is as defined above, and

[0093] Q is halogen, trifluoromethanesulphonyl or toluenesulphonyl,

[0094] with amines of formula (VII):

R⁵R⁶NH  (VII)

[0095] in which

[0096] R⁵ and R⁶ are as defined above,

[0097] or with

[0098] in the presence of bases, said process being characterized inthat the reaction is carried out in the presence of compounds of formula(I).

[0099] Preferred aryl compounds of formula (VI) are mono- ordisubstituted aromatic compounds. Examples of monosubstituted aromaticcompounds are chlorobenzene, bromobenzene, iodobenzene,bromonaphthalene, bromopyridine or bromoimidazole. Preferreddisubstituted aromatic compounds are those carrying substituents in the1,3- or 1,4-positions, for example 4-nitrochlorobenzene,4-methylchlorobenzene, 4-methoxychlorobenzene, 4-bromobenzonitrile,4-bromobenzoic acid, 3-ethoxybromobenzene, 3 -nitrobromobenzene or3-methyliodobenzene.

[0100] Particularly preferred aryl compounds of formula (VI) are 1,3- or1,4-disubstituted benzenes, for example 4-nitrobromobenzene,4-nitrochlorobenzene, 3-methylchlorobenzene, 3 -ethylbromobenzene or4-bromobenzonitrile.

[0101] Preferred amines of formula (VII) are aromatic amines such asaniline, N-methylaniline or 2,4,6-trimethylaniline; heteroaromaticamines such as aminopyridine, aminopyrimidine or aminopyrrole; cyclicamines such as piperidine, piperazine, N-methylpiperazine or morpholine;aliphatic secondary amines such as N,N-diethylamine, N,N-dibutylamine;or aliphatic primary amines such as n-hexylamine.

[0102] Particularly preferred amines of formula (VII) are aromaticamines such as aniline, heteroaromatic amines such as aminopyridine oraminopyrimidine, and cyclic amines such as piperidine, piperazine,N-methylpiperazine or morpholine.

[0103] The amine of formula (VII) is preferably added in approximatelystoichiometric amounts or in excess, based on the aryl compound offormula (VI). The amount of amine is preferably 1 to 3 equivalents andparticularly preferably 1.2 to 2 equivalents.

[0104] The bases used are preferably alkali metal and alkaline earthmetal hydroxides such as sodium hydroxide and potassium hydroxide,alkali metal and alkaline earth metal alcoholates such as lithiumtert-butylate, sodium tert-butylate or potassium tertbutylate, alkalimetal and alkaline earth metal carbonates such as potassium carbonate,alkali metal and alkaline earth metal amides, butyllithium,phenyllithium, sodium hexamethyldisilazide or lithiumhexamethyldisilazide, preferably alkali metal alcoholates or alkalimetal carbonates and particularly preferably sodium tert-butylate orpotassium carbonate. The base is preferably used in an amount of 0.5 to2 equivalents, especially of 1 to 3 equivalents and particularlypreferably of 1.2 to 2 equivalents, based on the aryl compound offormula (VI).

[0105] The compounds of formula (I) can be used for example in amountsof 0.01 to 10 mol %, preferably of 0.05 to 5 mol % and particularlypreferably of 0.1 to 2 mol %, based on the aryl compounds of formula(VI).

[0106] The compounds of formula (I) can be prepared separately or insitu. If the compounds of formula (I) are prepared in situ, thesupported ligands can be reacted in the presence of Pd(II) compounds togive the compounds according to the invention, the preferred amount ofsupported ligands used being 1 to 5 equivalents, based on the Pd(II)compounds. The in situ preparation does not require a further additionof base.

[0107] The reaction can be carried out with or without a solvent. If thereaction is carried out in a solvent, inert inorganic solvents arepreferred. It is preferred to use aromatic hydrocarbons such as toluene,xylenes, anisole or tetralin, and aliphatic ethers such astetrahydrofuran, dimethoxyethane, dioxane or tetrahydropropane.Particularly preferred solvents are toluene and xylenes. It is alsopossible to use solvent mixtures.

[0108] The reaction is preferably carried out without a solvent.

[0109] The reaction is preferably carried out at temperatures of 80° C.to 200° C., especially of 20° C. to 180° C. and particularly preferablyof 100° C. to 150° C.

[0110] The reaction preferably takes place under a conventional inertgas such as nitrogen, helium or argon.

[0111] The substituted arylamines are generally formed in good to verygood yields, for example of 50 to 99%, by the process according to theinvention. When the reaction has ended, the complexes of formula (I)according to the invention used as catalysts can be re-used in anotherreaction.

EXAMPLES Example 1 Not According to the Invention

[0112] Preparation ofdiiodo-di-(1-methyl-3-(ethoxycarbonylpropyl)-imidazolin-2-ylidene)-palladium(II)

[0113] 190 mg of Pd(OAc)₂ (1 mmol), 900 mg of NaI (6 mmol), 290 mg ofsodium tertbutylate (3 mmol) and 320 mg of1-methyl-3-(ethoxycarbonylpropyl)-imidazolium bromide (1 mmol) wereplaced in a Schlenk tube. 20 ml of tetrahydrofuran and 5 ml of ethanolwere added by means of a syringe. The reaction vessel was placed in anultrasound bath for 10 min and the reaction mixture was subsequentlystirred for a few hours at 22° C. and then for 14 h at 40° C. Theprogress of the reaction was monitored by thin layer chromatography(SiO₂; methylene chloride/1% methanol). When the reaction had ended, thesolvents were distilled off under vacuum and the residue was taken up inmethylene chloride and purified by column chromatography (SiO₂;methylene chloride/1% methanol).

Example 2

[0114] Preparation ofdiiodo-di-(1-methyl-3-(ethoxycarbonylpropyl)-imidazolin-2-ylidene)-palladium(II)supported on aminomethylpolystyrene/2% divinylbenzene

[0115] 5 ml of a 2 M solution of triethylaluminium in toluene (0.1 mmol)were added to 100 mg of aminomethylpolystyrene/2% divinylbenzene(loading 1 mmol). After a reaction time of 1 h, the supernatant wasdecanted off and 100 mg of the complex of Example 1 (0.2 mmol) in 10 mlof tetrahydrofuran were added. The reaction mixture was stirred for 16h, initially at 22° C. and then at 40° C., during which time thesupernatant became increasing decolourized while the polymer resinassumed a yellow-brown coloration. The reaction mixture was filteredthrough a glass frit and the residue was washed with methylene chloride,tetrahydrofuran, methanol, water, dimethylformamide and methanol again,and dried under vacuum.

Example 3

[0116] Preparation of 4-anilinobenzonitrile

[0117] 364 mg of 4-bromobenzonitrile (2 mmol), 205 mg of aniline (2.2mmol), 231 mg of sodium tert-butylate (2.4 mmol) and 50 mg of thesupported complex of Example 2 (0.04 mmol, 2 mol %) were placed in a 20ml flanged reaction vessel with a magnetic stirrer bead. The vessel wasclosed with a septum, evacuated and filled with an argon atmosphere. 6ml of degassed xylene were added by means of a syringe and the mixturewas stirred at 120° C. for 16 h. When the reaction had ended, themixture was extracted by shaking with water/methylene chloride, thecatalyst being separated off by filtration of the combined fractionsthrough a glass frit. The organic fractions were dried and analysed bygas chromatography.

[0118] Conversion: 70%

[0119] Yield of 4-anilinobenzonitrile: 270 mg

[0120] Selectivity in respect of 4-anilinobenzonitrile, based onconversion: >90%

Example 4

[0121] Preparation of 4-anilinobenzonitrile

[0122] The supported complex used in Example 3 was washed with methanol,tetrahydrofuran and diethyl ether and used in another reaction analogousto Example 3.

[0123] Conversion: 50%

[0124] Yield of 4-anilinobenzonitrile: 190 mg

[0125] Selectivity in respect of 4-anilinobenzonitrile, based onconversion: >90%

1. Compounds of formula (I):

in which X is halogen, trifluoromethanesulphonate, acetylacetonate oracetate, L is a radical of the formula P(D)₃, D being alkyl, cycloalkyl,aryl, aralkyl, alkylaryl or heteroaryl, or  a radical of the formulaN(E)₂, E being alkyl, cycloalkyl, aryl, aralkyl, alkylaryl orheteroaryl, or  a radical of formula (II):

B¹ and B² are identical or different and are a radical to complete aheterocycle, especially

R¹-R⁴ are identical or different and are a divalent radical from thegroup comprising alkyl, cycloalkyl, aryl, aralkyl and alkylaryl, each ofwhich is optionally substituted by COO—(C₁-C₄-alkyl), O(C₁-C₄-alkyl) orCONH₂, and A¹-A⁴ are identical or different and are hydrogen or achemical bond from the group comprising —CONH—, —CO—O—OC—, —COO—, —O—and

 via which the complex is bonded to the support, with the proviso thatat least one A is other than hydrogen.
 2. Compounds according to claim 1in which X is halogen, L is a radical of the formula P(D)₃, D being aradical from the group comprising cyclohexyl, phenyl, naphthyl andtolyl, or a radical of formula (II):

B¹ and B² are identical or different and are

R¹-R⁴ are identical or different and are a divalent radical from thegroup comprising alkyl, cycloalkyl, aryl, aralkyl and alkylaryl, each ofwhich is optionally substituted by COO—(C₁-C₄-alkyl), O(C₁-C₄-alkyl) orCONH₂, and A¹-A⁴ are identical or different and are hydrogen or achemical bond from the group comprising —CONH—, —CO—O—OC—, —CO—, —O— and

 via which the complex is bonded to the support, with the proviso thatat least one A is other than hydrogen and the support is selected fromthe group comprising inorganic supports and polymeric supports. 3.Compounds according to claim 1 or 2 in which X is I, L is

B¹ is

R¹ and R³ are identical and are a divalent radical —(C₁-C₆-alkyl)—,preferably —CH₂—, R² and R⁴ are identical and are a divalent radical—(C₁-C₆-alkyl)-, preferably —(CH₂)₃—, A¹ and A³ are identical and arehydrogen, and A² and A⁴ are identical and are a chemical bond from thegroup comprising —CONH—, —CO—O—OC—, —COO—, —O— and

 and the support is an inorganic support from the group comprisingsilica gel, magnesium oxide and aluminium oxide, or a polymeric supportfrom the group comprising polyester, polyether, polyethylene,polypropylene and polystyrene.
 4. Process for the preparation ofcompounds according to claims 2 and 3, characterized in that compoundsof formulae (III) and (IV):

in which B¹ and B² are identical or different and are a radical tocomplete a heterocycle, especially

R¹-R⁴ are identical or different and are a divalent radical from thegroup comprising alkyl, cycloalkyl, aryl, aralkyl and alkylaryl, each ofwhich is optionally substituted by COO—(C₁-C₄-alkyl), O(C₁-C₄-alkyl) orCONH₂, G¹-G⁴ are identical or different and are hydrogen, COOH,CO—O—CO(C₁-C₄-alkyl), COO(C₁-C₄-alkyl), COCl, CO(C₁-C₄-alkyl), COH, NH₂,NH(C₁-C₄-alkyl), OH, Si(O—C₁-C₄-alkyl)₃ or OCN, with the proviso that atleast one G is other than hydrogen, and Y is an anion from the groupcomprising Cl, Br, I, C₁-C₄-alkylsulphonate, C₆-C₁₄-arylsulphonate,hexafluorophosphate and tetrafluoroborate, or compounds of formulae(III) and P(D)₃, D being alkyl, cycloalkyl, aryl, aralkyl, alkylaryl orheteroaryl, or compounds of formulae (III) and N(E)₂, E being alkyl,cycloalkyl, aryl, aralkyl, alkylaryl or heteroaryl, are reacted withPd(II) compounds in the presence of a base, and the reaction product isimmobilized on a support which has groups reactive towards G, other thanhydrogen.
 5. Process for the preparation of compounds according toclaims 1 to 3 , characterized in that compounds of formula (III) orcompounds of formulae (III) and (IV):

in which B¹ and B² are identical or different and are a radical tocomplete a heterocycle, especially

R¹ -R⁴ are identical or different and are a divalent radical from thegroup comprising alkyl, cycloalkyl, aryl, aralkyl and alkylaryl, each ofwhich is optionally substituted by COO—(C₁-C₄-alkyl), O(C₁-C₄-alkyl) orCONH₂, G¹-G⁴ are identical or different and are hydrogen, COOH,CO—O—CO(C₁-C₄-alkyl), COO(C₁-C₄-alkyl), COCl, CO(C₁-C₄-alkyl), COH, NH₂,NH(C₁-C₄-alkyl), OH, Si(O—C₁-C₄-alkyl)₃ or OCN, with the proviso that atleast one G is other than hydrogen, and Y is an anion from the groupcomprising Cl, Br, I, C¹-C₄-alkylsulphonate, C₆-C₁₄-arylsulphonate,hexafluorophosphate and tetrafluoroborate, are immobilized on a supportwhich has groups reactive towards G, other than hydrogen, and withPd(II) compounds and—in the case where only compounds of formula (III)are immobilized on a support—with P(D)₃, D being alkyl, cycloalkyl,aryl, aralkyl, alkylaryl or heteroaryl, or N(E)₂, E being alkyl,cycloalkyl, aryl, aralkyl, alkylaryl or heteroaryl, in the presence of abase.
 6. Process according to claims 4 and 5, characterized in that thePd(II) compound is a compound from the group comprising palladiumacetate, halides, nitrate, carbonate, ketonate and acetylacetonate. 7.Process according to one or more of preceding claims 4 to 6 ,characterized in that the base is a compound from the group comprisingalkali metal alcoholate, alkaline earth metal alcoholate, alkali metalcarbonate and alkaline earth metal carbonate.
 8. Process according toone or more of preceding claims 4 to 7 , characterized in that thesupport is an inorganic support or a polymeric support.
 9. Processaccording to one or more of preceding claims 4 to 8 , characterized inthat the support is selected from the group comprising silica gel,magnesium oxide, aluminium oxide, polystyrene, polyether, polyester,polyethylene and polypropylene.
 10. Use of the compounds according toclaims 1 to 3 as catalysts.
 11. Use according to claim 10 for thepreparation of arylamines.
 12. Process for the preparation of arylaminesof formula (V): Ar—NR⁵R⁶  (V) in which Ar is phenyl, naphthyl, pyridyl,pyridazinyl, pyrimidyl, pyrazinyl, pyrryl, thiophenyl, furyl,imidazolyl, oxazolyl, isoxazolyl, thiazolyl or triazolyl, and theabovementioned radicals optionally carry one or more substituents fromthe group comprising C₁-C₈-alkyl, C₃-C₈-cycloalkyl, C₁-C₈-alkoxy,C₁-C₈-acyloxy, C₆-C₁₄-aryl, C₆-C₁₄-aryloxy, halogen, C(halogen)₃, NO₂,NH₂, NH(C₁-C₈-alkyl), N(C₁-C₈-alkyl)₂, NHCOR, NHCHOC, NHCOOH, NHCOOR,OH, CN, COOH, CHO, CO(C₁-C₈-alkyl), CO(C₆-C₁₄-aryl), CO₂(C₆-C₁₄-aryl),CO₂(C₁-C₈-alkyl), CONH₂, SO₃H, SO₂R, SOR, PO(C₆-C₁₄-aryl)₂,PO(C₁-C₈-alkyl), Si(C₁-C₈-alkyl)₃ and heteroaryl, R being C₁-C₄-alkyl,and R⁵ and R⁶ independently of one another are hydrogen, C₁-C₁₂-alkyl,C₃-C₈-cycloalkyl or C₆-C₁₄-aryl, the abovementioned radicals optionallycarrying one or more substituents from the group comprising C₁-C₈-alkyl,C₃-C₈-cycloalkyl, C₁-C₈-alkoxy, C₁-C₈-acyloxy, C₆-C₁₄-aryl,C₆-C₁₄-aryloxy, halogen, C(halogen)₃, NO₂, NH₂, NH(C₁-C₈-alkyl),N(C₁-C₈-alkyl)₂, NHCOR, NHCHO, NHCOOH, NHCOOR, OH, CN, COOH, CHO,CO(C₁-C₈-alkyl), CO(C₆-C₁₄-aryl), CO₂(C₆-C₁₄-aryl), CO₂(C₁-C₈-alkyl),CONH₂, SO₃H, SO₂R, SOR, PO(C₆-C₁₄-aryl)₂, PO(C₁-C₈-alkyl),Si(C₁-C₈-alkyl)₃ and heteroaryl, R being C₁-C₄-alkyl, or  together are aring having up to 5 C atoms, it being possible for one C atom to bereplaced by O or N, by reacting aryl compounds of formula (VI):Ar—Q  (VI) in which Ar is as defined above, and Q is halogen,trifluoromethanesulphonyl or toluenesulphonyl, with amines of formula(VII): R⁵R⁶NH  (VII) in which R⁵ and R⁶ are as defined above, or with

in the presence of bases, said process being characterized in that thereaction is carried out in the presence of compounds of formula (I)according to claims 1 to 3 .
 13. Process according to claim 12 ,characterized in that the aryl compounds of formula (VI) used are 1,3-or 1,4-disubstituted benzenes.